package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;


import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{

    public static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";
    public static final String KEY_PREFIX = "lock:";
    //DefaultRedisScript是RedisScript的实现类
    public static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unLock.lua"));//设置脚本位置
        UNLOCK_SCRIPT.setResultType(Long.class);//配置返回值
    }

    private String name;//不同业务有不同的锁，业务name即为锁的name
    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取线程表示
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue().
                setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        //防止拆箱操作，不能直接返回success
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unLock() {
        //调用Lua脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name), //转成List类型
                ID_PREFIX + Thread.currentThread().getId());
    }

//    @Override
//    public void unLock() {
//        //获取线程标识
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//        //获取锁中的标识
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//        //判断标识是否一致
//        if(threadId.equals(id)){
//            //释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }
}
